His Oscar-winning film The Mission chronicled the travails of Jesuit priests attempting to convert the indigenous peoples of the Brazilian jungle. Now British film-maker Roland Joffé is to return to the subject of religion with a film about one of the most mysterious organisations within the Roman Catholic church: Opus Dei.

Joffé is to direct a biopic of the Spanish priest Josemaría Escrivá de Balaguer, who founded the organisation in 1928. Escrivá was canonised in 2002, 27 years after his death, by Pope John Paul II, who declared that he "counted among the great witnesses of Christianity".

The film, There Be Dragons, has received Opus Dei's blessing, but has not been funded by the organisation, its former information officer, Luis Gordon, told the Independent.

"The film team asked us for help in gathering information and we gave them access to the documentation. That's the beginning and end of our collaboration with this film," Mr Gordon said.

Opus Dei, which teaches the belief that everyone is called to holiness and that ordinary life is a path to sanctity, has been the subject of some controversy in the film-making world in recent years. It was portrayed as being part of a sinister international conspiracy in the 2006 film The Da Vinci Code, though officials pointed out that the Dan Brown novel, from which the movie was adapted, was based on inaccurate information.

The organisation is often criticised for its alleged secretiveness, while its founder's predilection for indulging in mortification of the flesh has caused unease. Escrivá, whose maxim was "Loved be pain. Sanctified be pain. Glorified be pain!", is said to have once flailed himself more than a thousand times.

There Be Dragons, according to production notes published in the Spanish newspaper El País, will centre on the early years of Escrivá's life during the 1930s. It's described as "a drama full of passion, betrayal, love and religion [that] reveals the importance and eternal power of forgiveness".

There has been criticism of the film, however, from an anti-Opus blog of former members who say they were "mentally and spiritually diminished" by the organisation.

"This is a propaganda film written and supervised by members of Opus Dei in a desperate attempt to clean up its battered image in the eyes of public opinion," wrote one blogger.

There Be Dragons is due to shoot in the next few months at the pilgrimage site of Luján in Argentina, and in Spain. British actor Charlie Cox, who appeared in the 2007 fantasy Stardust, will take one of the main roles.

Joffé's early successes – he was nominated for Oscars as director for 1986's The Mission and 1984's The Killing Fields – have been tempered by perceived failures in subsequent years. He won the Razzie for worst remake or sequel for 1995's The Scarlet Letter and was nominated again in 2007 for the thriller Captivity, criticised by many as one of the worst examples of the torture porn genre.